统一身份认证及其在校园网中的应用

基于校园网的应用系统的建设带来一个用户需要许多账号和密码的问题,使用统一身份认证系统可以实现用户单点登录、多种方式认证.对统一身份认证服务的组成和实现进行了论述,并给出了一个使用统一身份认证的校园门户的结构框架.     

高校校园网统一身份认证系统的安全研究——以山西大学商务学院校园网为例

网络身份认证技术的逐渐成熟,为高校校园网实现统一身份认证技术和"一卡通"系统提供了网络基础.校园网的应用现状对身份认证系统提出了现实需求.本文将通过介绍山西大学商务学院校园网建设的总体设计思想与功能,针对校园网内用户访问量大且多数用户访问权限有限,以及身份认证系统在实施过程中存在的问题,提出基于802.1x的统一身份认证系统的安全管理方案.     

校园网统一身份认证系统的探讨

随着校园网应用的扩大,各种基于网络的应用系统广泛地应用于校园的教学、科研和管理中,但是各种应用系统独立的用户管理和认证策略,不仅给用户使用和应用系统维护带来不便,而且容易影响校园网的安全,因此,建立统一的身份认证系统,对网络用户实行集中管理、统一认证和授权是网络发展的趋势.就统一身份认证系统的结构、实现方法和安全措施方面进行探究,以保证用户在使用方便的基础上,有效地维护校园网的安全.     

Active Directory和Kerberos的校园网络统一认证的实现

随着校园网络建设规模的不断发展,各种基于校园网络的应用也越来越多,也就提出了用户对校园网络统一身份认证的要求.文章在分析Active Directory和Kerberos协议的基础上,提出了一个适用校园网络支持单点登陆的安全认证架构,进行用户的统一授权管理.     

LDAP协议下多模型融合校园认证系统的研究与实现

建立一个统一认证系统,对网络用户实行统一管理、认证和授权是数字化校园建设中的一个重要内容。在介绍了统一认证模型类型以及用于存放认证信息的LDAP目录服务协议的基础上,结合当前校园网建设的实际情况,设计了一个基于LDAP协议的校园网统一身份认证系统。在统一认证的过程中,应用不同访问模式和传输技术,通过多模型融合方式实现了邮件服务、互联网访问控制、VPN服务等典型应用的统一认证服务,并将该系统模式推广到校内的一些专用网络应用中,为后续的一站式认证奠定了基础。     

校园网用户身份统一认证系统的设计

通过对青岛大学的网络环境上运行的应用系统用户身份认证的情况进行分析,设计了一种适合于青岛大学统一身份认证系统的系统模型。该系统综合应用了轻重量级目录服务、Web Services、SOAP和XML技术,将基于理论上的解决方案应用到青岛大学校园网建设中,并具体分析和实现了校园网中B/S模式的应用系统的统一身份认证。     

基于目录服务的数字化校园统一身份认证

本文首先分析高校数字化校园中统一身份认证系统建设的必要性,简要地介绍了LDAP协议及其相关的技术,提出了基于LDAP的校园网统一身份认证机制实现了对校园网用户统一身份管理统一身份认证。     

基于双因素特征的信息安全身份认证技术研究

身份认证是网络信息安全技术的一个重要方面．本文介绍了基于动态密码技术的双因素特征身份认证在信息安全中的应用,并为了保证身份认证信息在网络中安全传输,设计了一个安全有效的基于秘密信息传输的身份认证通讯架构。     

浅谈校园用户身份管理系统设计与应用

伴随着信息化的不断发展,很多高校都广泛使用基于B/S架构的各类应用系统,而这些应用系统大都各自保存一套不同的用户身份认证方式,这就影响了系统使用的效率,并给整个校园系统带来了很多不安全隐患。本文提出用户身份统一管理模式,它为各类应用系统提供统一的用户身份管理和登录入口,并根据用户输入的身份信息,通过SSO认证模块和LDAP中的用户基本信息进行验证,为整个校园应用系统提供了安全保障。     

Web服务统一身份认证协议

为实现基于Web服务的多应用系统的用户身份安全认证,采用统一身份认证方案,结合已有的Web服务安全规范,提出了一个多应用环境下的基于Web服务的统一身份认证协议Web Services Single Sign-on(WSSS),并详细描述了WSSS的模型、消息定义及流程,采用形式化方法对协议进行了表示和分析,同时对协议进行了安全性分析．WSSS所定义的统一身份认证服务可用于为网络中各种基于Web服务的应用提供Web服务的安全身份认证。     

地理元胞自动机及空间动态转换规则的获取

 以东莞市黄江等镇城市发展为例,利用逐步逻辑回归方法,获取分区的元胞自动机动态规则,用分区的动态规则CA模拟了研究区1988-2004年的城市扩张,采用逐点对比法和Moran I指数对模拟结果进行了评价。结果表明,分区的空间动态转换规则比统一的静态转换规则能获得更高的模拟精度,动态转换规则克服了传统静态转换规则无法反映区域内部城市发展差异的缺陷。     

Adaptive liquid microlenses activated by stimuli-responsive hydrogels

Despite its compactness, the human eye can easily focus on different distances by adjusting the shape of its lens with the help of ciliary muscles. In contrast, traditional man-made optical systems achieve focusing by physical displacement of the lenses used. But in recent years, advances in miniaturization technology have led to optical systems that no longer require complicated mechanical systems to tune and adjust optical performance. These systems have found wide use in photonics, displays and biomedical systems. They are either based on arrays of microlenses with fixed focal lengths, or use external control to adjust the microlens focal length. An intriguing example is the tunable liquid lens, where electrowetting or external pressure manipulates the shape of a liquid droplet and thereby adjusts its optical properties. Here we demonstrate a liquid lens system that allows for autonomous focusing. The central component is a stimuli-responsive hydrogel integrated into a microfluidic system and serving as the container for a liquid droplet, with the hydrogel simultaneously sensing the presence of stimuli and actuating adjustments to the shape--and hence focal length--of the droplet. By working at the micrometre scale where ionic diffusion and surface tension scale favourably, we can use pinned liquid-liquid interfaces to obtain stable devices and realize response times of ten to a few tens of seconds. The microlenses, which can have a focal length ranging from -infinity to +infinity (divergent and convergent), are also readily integrated into arrays that may find use in applications such as sensing, medical diagnostics and lab-on-a-chip technologies.     

高能物理研究所校园网格计算环境设计研究

自1996年VAX小型机退役后,已建立了几套PC-Farm系统,它们分别为不同的物理实验做数据分析所使用,运行不同的作业管理系统如NQS、PBS和Condor等.由于各个实验数据分析对计算系统使用的时间不同,致使整个系统的使用效率不高.为了使这些分立运行的系统发挥更好的效用,使用网格计算技术将这些分立的计算资源整合起来,形成一个计算能力更强大的计算系统,以便这些实验组能够在更大范围内对计算资源共享.给出了校园网格计算环境的硬件配置、体系结构等设计方案,以及各个组件的功能等.     

土地系统工程的理论与方法探析

随着人类对土地的开发利用的程度和强度不断加强,人地关系日益紧张,迫切的需要将系统工程的方法引入土地系统,即土地系统工程,从整体性、系统性的高度对土地系统进行管理,最终实现土地系统综合效益最优化.文章提出了土地系统工程的基本理论框架,论述了土地系统工程的工作步骤和方法体系.土地系统工程为现代土地规划、开发、利用、整治、管理、保护和评价提供决策依据,对协调人地关系,实现土地的可持续利用具有重要意义.     

基因表达系统与转基因动物乳腺反应器

出于研究、医疗或工业目的，常常需要大量置备各种生物活性蛋白质，为此已经建立了多种基因工程表达系统，如微生物发酵系统、真核细胞培养系统、转基因植物表达系统和转基因动物表达系统等。近几年，利用转基因动物作为生物反应器由乳汁中生产蛋白药物的研究取得了很大进展，有多种动物可被用于转基因。基本过程是将基因构件显微注射到单细胞期受精卵，基因构件以一定几率整合到受体基因组中。通常转基因和其表达模式可忠实地遗传。许多蛋白将以高浓度低成本由转基因家畜的奶中生产。这些转基因动物与传统的动物细胞培养和细菌发酵技术相比尤显高效。乳腺能完成包括二硫桥形成、酰胺化、羧基化和糖基化在内的翻译后修饰，１头转基因羊就是１套发酵罐。据预测，到２０１０年由转基因动物生产的蛋白药物占全部基因工程药物的比率将增长到９５％以上。     

Towards consistent machine translation of abbreviated terms in scientific literature

Scientific literature often contains abbreviated terms in English for brief.Machine translation(MT) systems can help to share knowledge in different languages among researchers.Current MT systems may translate the same abbreviated term in different sentences into different target terms.MT systems translate the abbreviated term in two ways:one is to use translation of the full name,the other is to use the abbreviated term directly.Abbreviated terms may be ambiguous and polysemous,and MT systems do not have an explicit strategy to decide which way to use without context information.To get the consistent translation for abbreviated terms in scientific literature,this paper proposes a translation model for abbreviated terms that integrates context information to get consistent translation of abbreviated terms.The context information includes the positions of abbreviated term and domain attributes of scientific literature.The first abbreviated term is translated in full name while the latter ones of the same abbreviated term will show the abbreviated form in the translation text.Experiments of translation from Chinese to English show the effectiveness of the proposed translation model.     

转子--电磁动力吸振器系统的非线性控制

用电磁动力吸振器可实现对转子振动的在线控制。但是，当系统受到外部激励时，系统可能处于大幅度运动状态，致使转子与吸振器相接触而失控，因而对这类系统采用非线性控制便显得十分必要。在对转子-电磁动力吸振器实行线性控制的基础上，采用非线性补偿控制。数字仿真结果表明，非线性补偿控制可使转子-电磁动力吸振器达到更好的控制效果。     

Recent progress in the simulation of microstructure evolution in titanium alloys

Titanium alloys (Ti-alloys) have complicated multiscale hierarchical structures that enabled a variety of excellent mechanical properties,such as strength,ductility,fatigue and creep resistance etc.But how are the microstructures formed under different conditions,and what are the inter-dependencies between the properties and various microstructures are not easy to reveal solely by experiments.In the last two decades,multiscale modeling and simulation have been carried out,and promoted our understanding of the microstructure formation and their deformation mechanisms.In the present paper,recent progresses are reviewed and future trends analyzed,on the simulation of microstructure evolution in Ti-alloys and how these are combined with experimental characterization and verification,to reveal the controlling factor and hidden mechanism under various deformation/transformation conditions;and to promote the optimization of thermo-mechanical processing.It is recognized that,future computations should pay more attention to the bottleneck problems in the design and application of Ti-alloys and play a more important role in identifying specific controlling factors and revealing the relevant working mechanisms in more complicated process,such as thermo-mechanical processing,powder metallurgy or additive manufacturing.In addition,artificial intelligence (AI) may assist the screening of new materials.These efforts may accelerate the development and application of new alloys,and at lower cost,especially for Ti-alloys in aero/space engine satisfying multiple performance requirements such as strength,toughness,creep resistance,fatigue life and other properties.     

A general mechanism for perceptual decision-making in the human brain

Findings from single-cell recording studies suggest that a comparison of the outputs of different pools of selectively tuned lower-level sensory neurons may be a general mechanism by which higher-level brain regions compute perceptual decisions. For example, when monkeys must decide whether a noisy field of dots is moving upward or downward, a decision can be formed by computing the difference in responses between lower-level neurons sensitive to upward motion and those sensitive to downward motion. Here we use functional magnetic resonance imaging and a categorization task in which subjects decide whether an image presented is a face or a house to test whether a similar mechanism is also at work for more complex decisions in the human brain and, if so, where in the brain this computation might be performed. Activity within the left dorsolateral prefrontal cortex is greater during easy decisions than during difficult decisions, covaries with the difference signal between face- and house-selective regions in the ventral temporal cortex, and predicts behavioural performance in the categorization task. These findings show that even for complex object categories, the comparison of the outputs of different pools of selectively tuned neurons could be a general mechanism by which the human brain computes perceptual decisions.     

Rac function and regulation during Drosophila development

Rac GTPases regulate the actin cytoskeleton to control changes in cell shape. To date, the analysis of Rac function during development has relied heavily on the use of dominant mutant isoforms. Here, we use loss-of-function mutations to show that the three Drosophila Rac genes, Rac1, Rac2 and Mtl, have overlapping functions in the control of epithelial morphogenesis, myoblast fusion, and axon growth and guidance. They are not required for the establishment of planar cell polarity, as had been suggested on the basis of studies using dominant mutant isoforms. The guanine nucleotide exchange factor, Trio, is essential for Rac function in axon growth and guidance, but not for epithelial morphogenesis or myoblast fusion. Different Rac activators thus act in different developmental processes. The specific cellular response to Rac activation may be determined more by the upstream activator than the specific Rac protein involved.